The usual construction of flat end low-sloped roofs involves laying down a series of layers, or laminations, of various materials in sequence. A sub-roof structure providing the necessary strength is first put in place. This may be in the form of poured or pre-cast concrete slabs, or a combination of wood and possible plywood that presents a solid surface on which the rest of the laminations are deposited. The first of these is usually 4 ft..times.8 ft. insulation panels of conventional foamed material. These panels are fairly soft, and will not tolerate high localized pressure without significant deformation. Anything tending to compress these panels substantially will alter their insulation characteristics, and interfere with the planar uniformity of the completed roof. The insulation panels must be secured in place. This is usually done by drilling a pattern of holes through the panels, and into the sub-roof structure to receive standard fastenings. Each panel will probably be secured at about 16 points, which obviously presents a cost problem. This is particularly true when the sub-roof is some form of concrete, and thus presents considerable resistance to the drilling process. The usual practice has been to run these holes in with hand-held drills, as the softness of the insulation panels has always been thought to preclude the use of machinery. The panels will withstand the pressure per square inch represented by a man walking around on soft-soled shoes, but not the heavier concentrations of pressure that normally are associated with portable machinery. The situation prior to the present invention has thus involved the laborious drilling of all of these holes in each 4 ft..times.8 ft. panel, on a one-by-one basis.
Pattern drilling machines are well known in factories and machine shops. They are sometimes referred to as template drills, and most often involve a plate laid out with a pattern of holes associated with a particular job, and drilling spindles mounted at each of these locations. The usual arrangement is a common drive for all of these spindles, either through gearing or with an arrangement of belts. It has apparently occurred to no one to utilize this principle in the securing of insulation for flat roofs, because of the difficulty of picking such machines up, and depositing them on a roof under construction. This is compounded by the obvious problem that the weight of such machines would create as it moved across the soft insulation panels. The present invention provides a machine that makes the gang drilling of holes in the insulation panels a practical procedure.